High-speed classification and checkweighing system

ABSTRACT

A system for monitoring packages and maintaining constant weight is disclosed wherein the checkweighing scale services at least two weighing scales with a scale selector switch responsive to the packaging means and independent of the package being checkweighed. The scale selector switch operates in synchronism with the scale dump timing switch also responsive to said packaging means to maintain the operations in step and adjustment means is provided to vary the number of bags between the packaging means and the checkweighing scale. A drive circuit includes check switch means responsive to the packaging means and independent of the package to energize companion reject-accept or classification and correction circuits to maintain the actions concurrent; a scale return circuit is provided; and a photoelectric sensing circuit is provided in said correction circuit to disable the same on a dry cycle. Holding relays maintain the companion circuits energized and delay means is provided in the drive circuit for the adjusting means of the scale being standardized to prevent switching of the classification, correction and scale return action during a single packaging cycle.

United States Patent CLOSES \F PACKKGE [72] Inventors Nelson R. Henry;Primary ExaminerRichard B. Wilkinson Donald R. Middour, both of Decatur,Ga. Assistant Examiner-George H. Miller, Jr. [21] Appl. No. 048,339Anomey-Lowe and King [22] Filed June 22, 1970 [45] Patented Nov. 16,1971 V. [73] Asslgnee g: Company ABSTRACT: A system for monitoringpackages and maintainu ing constant weight is disclosed wherein thecheckweighing scale services at least two weighing scales with a scaleselector I54] "IGWSPEED CLASSIFICATION AND switch responsive to thepackaging means and independent of CHECKWEIGHING SYSTEM the packagebeing checkweighed. The scale selector switch 21 Claims, 1D"Mnangoperates in synchronism with the scale dump timing switch alsoresponsive to said packaging means to maintain the [52] U.S. Cl .loperations in step and adjustment means is providcd to vary 209/121 thenumber of bags between the packaging means and the 8 19/52 checkweighingscale. A drive circuit includes check switch OI 52, means responsive tothe packaging means and indepgndent of 60; 209/121 the package toenergize companion re ject-accept or classifica- 56 R t Cl ed tion andcorrection circuits to maintain the actions concur- 1 e rent; a scalereturn circuit is provided; and a photoelectric UNITED STATES PATENTSsensing circuit is provided in said correction circuit to disable2,688,458 9/1954 Schieser et al 177/50 the same on a dry cycle. Holdingrelays maintain the com- 2,818,888 1/1958 Atwood et al. 177/52 X panioncircuits energized and delay means is provided in the 3,225,847 12/1965Vergobbi et al. 177/52 drive circuit for the adjusting means of thescale being stan- 3,434,595 3/1969 Seaborn et al.. 177/52 X dardized toprevent switching of the classification, correction 3,484,813 12/ 1969Davies 177/50 and scale return action during a single packaging cycle.

40 ACCEPT m2 VALVE SOL.

Y:3 Q h n ii [Queer Auz VALVE SOL. a so J REJECT-MCEPT w $7 1 i efiliiwH0 9 W31 RY-Ia V 5% x corzraEcnoN NR swnm (OPEN 10o mom) 1 ial I l 54 I6124 la n I CHECK swam r PkCKAGING 1 Kane PK6.=IBO) n. mcume Anlafi \L?DFUVE DRWE MQ-[OQ 1 \B l 88 l l SCMI: SELECTOR TlMNG 5W. I l W\TCH (onePKGr-QO") mo Rm, l l -1 \%P"" 1% 1 4*? 14 l rzr-ea coszizecnoN i sea l L,1 (SCALE .25) I gs & lN(1lEk r l mew 89 \NC. e k ii'tem DECQEksE i i 1isi fr RY-Sa RY-4a l I mcrze 5i: 1 90 I (ltlic. pm I g. \NT ADJ i 1 Sam1 I: fiiioi't RELAY CONTACT Emma J (SCALE m l l 13 ON scma PAN l0HIGH-SPEED CLASSIFICATION AND CHECKWEIGI-IING SYSTEM The presentinvention relates to weighing systems, and more particularly, to acheckweighing system having classification and correction circuits foradjusting the weighing scales of a packaging machine or machines.

BACKGROUND OF THE INVENTION In packaging machines for filling packagesor containers with a predetermined weight of material, there exists aproblem of maintaining the package-filling means in adjustment todispense accurate weight charges over an extended period. Variousfactors affect the accuracy of the packagefilling means, such as thechanges in the physical properties of the material being packaged, theatmospheric conditions and the build up of residue in the packagingmachine, particularly the weighing hopper. Various checkweighing systemshave been devised wherein the finished packages from the packagingmachine are received in sequence at a checkweighing station andmonitored. In response to the deviation from set standards, the packagemay be classified, that is either accepted or rejected, and a correctionsignal is fed back to the weighing scale in the packaging machine toadjust the weight setting in accordance with the deviation.

Since the filling operation of a packaging cycle is the limiting factorinsofar as speed of the packaging machine is concerned, there areproposals to provide multiple filling stations in a packaging machine inorder to fill a plurality of packages at a time or in succession.Likewise in order to improve the efficiency of a packaging operation, itis proposed to feed the output from multiple machines to a singleconveyor for checkweighing and packaging into multiple package cartons.However, with the introduction of such multiple sources of packagefilling an obvious new problem is introduced; that of identifying theparticular filling mechanism which has produced a package beingcheckweighed at any given time.

The first solution suggested to one skilled in the art and one way inwhich the problem has been attached heretofore, is to providephotoelectric circuits or similar detectors to sense the presence ofeach filled bag and distribute the correction signal back to the fillingmeans in accordance with the packages actually counted and checkweighed.While such prior art systems are acceptable under ideal conditions, theoccurrence of a dry cycle, that is where a package is not formed at onescheduled interval, or the introduction or removal of packages to thesystem by operating personnel, causes the checkweighing system to getout of step with the packaging machine whereby faulty signals are fedback to the filling devices or scales. Without some correction, thefaulty signals eventually cause a complete disruption of the fillingcycles since each erroneous signal fed back tends to compound itselfuntil the adjustments are set at the lowest or highest point therebycontinuously producing grossly underweight or overweight packages.

Several schemes have been devised to attempt to overcome theidentification problem. In the U.S. Pat. to Davies No. 3,484,813, issuedDec. 16, 1969, is disclosed one such method wherein a complex spacingarrangement between groups of packages is adopted and memory circuitsare provided so that at the end of each group a reset is made therebylimiting any such identification error to only those packages in thegroup. While such a system thus approaches solution of the problem, asimpler and more efficient system wherein even an error in a group ofpackages does not have to be accepted, is clearly needed to advance theart of high-speed checkweighing whereby multiple filling devices may beput to greater use.

Another system is shown in the U.S. Pat. to Cunningham No. 3,! [5,165wherein an extensive computer-type circuit is set up to control thecheckweighing system and parts of the packaging machine. In this system,such critical functions of the packaging machine as forming the bag,setting the contents and code dating are operated separately so thatagain only under ideal conditions is the system capable of preventingout-of-step operation. This prior art system besides being veryexpensive is not adapted to incorporation into existing machines havingno adaptation for computer control. In system where use is made, thespeed of the computer must be constantly adjusted to attempt to matchthe speed of the packaging machine, particularly afier change of themachine to run a different size bag or package.

Furthermore, there is need for improvement in the simplification andperformance of systems wherein reject-accept or classification circuitis combined with the correction circuit. Such companion circuits shouldbe designed for concurrent and compact operation in the packaging cycle,but with the elimination of switching once a reading from thecheckweighing scale is provided during any one packaging cycle.

OBJECTIVES OF THE INVENTION Accordingly, it is one object of the presentinvention to provide a checkweighing system that overcomes theabove-mentioned problems.

Another object of the present invention is to provide a checkweighingsystem responsive to the packaging means itself operative to accuratelyidentify packages from a plurality of sources and to feed backcorrecting signals to automatically reset the weight setting of thedevice that filled the package being checkweighed.

It is another object of the present invention to provide a system havingcompanion reject-accept and correction circuits capable of high-speedoperation without midcycle switching.

It is still another object of the present invention to provide acheckweighing system having a first and second sensor to control therespective reject-accept and correction functions and a check switch tocontrol the energizing of the circuits having said sensors.

BRIEF DESCRIPTION OF THE INVENTION Thus, in accordance with the presentinvention a high-speed checkweighing system is provided wherein anindependently operating packaging machine controls the entire operationof the checkweighing system. This system performs a checkweighingoperation only in response to the formation of a package by thepackaging machine and is insensitive to inserting or removing bags fromthe checkweighing system. A scale selector switch is provided whichoperates in synchronism with the scale dump timing switch and both ofwhich are continuously rotated at the selected speed in response to thepackaging machine rather than an outside source as in the prior art.Thus, any speed of the machine to forma particular size bag or in orderto obtain the maximum efiiciency of the machine may be selected withoutregard to the effect of the checkweighing system which automaticallyremains in step under all conditions.

In order to adapt the checkweighing system to any number of packagesbetween the packaging machine and the checkweighing means, there isprovided a phase adjustment means in the operating means for theselector switch and the timing switch of the packaging machine. As anexample of one case where there are two filling means employed in asingle packing means, the number of packages between the packaging meansand the checkweighing means may be even, i.e., zero, two, four, etc.;thus, the filling of a package by the first filling means isaccomplished in point of time by checkweighing of a package filled bythe second filling means and the appropriate correcting of the same. Inthis situation. the checkweighing means can then be used with or withoutan intermediate conveyor without adjustment as long as the conveyorspaces remain an even number. The scale selector switch and the timingswitch are 180 degrees out of phase for proper operation in thisinstance. When an odd number of intermediate packages are preferred, thesame filling means is operating as is being corrected and the switchesare in phase.

Further, in accordance with the present invention, check switch meansresponsive to said packaging means and independent of said packages isutilized in a drive circuit to energize the companion classification andcorrection circuits to maintain maximum efficiency of operating time andin-step operation with the packaging means. The relay in said drivecircuit is selected to have a dropout time characteristic sufficientlyslower than the pickup time characteristic of the relays employed in theclassification and correction circuits whereby the operation and settingof the classification and checkweighing circuits is assured prior tobeing energized by the drive circuit to classify the packages and todrive the reversible servomotor.

A photoelectric sensing circuit is provided at the scale pan of thecheckweighing scale to disable the correction circuit in the event of adry cycle occuring. This prevents a false correction signal being sentto the reversible servomotor for the selected scale, but at the sametime allows operation of the classification circuit to generate anairblast across the scale pan to clear the same for the next cycle.

Still other objects and advantages of the present invention will becomereadily apparent to those skilled in this art from the followingdetailed description, wherein we have shown and described only thepreferred embodiment of the invention, simply by way of illustration ofthe best mode contemplated by us of carrying out our invention. As willbe realized, the invention is capable of other and different embodimentsand its several details are capable of modification in various obviousrespects, all without departing from the invention. Accordingly, thedrawing and description are to be regarded as illustrative in nature,and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic diagram of thecheckweighing system constructed in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION With reference now to the singlefigure of the drawing, there is shown a diagram in schematic form of acheckweighing system utilizing the principles of the present invention.An independently operating packaging machine is shown within a brokenline outline, generally designated by the reference numeral 10, whichpackaging machine may be a form and fill type wherein a continuous webof sheet material is formed into a tube and a sealing carriage is usedto bring sealing jaws together to form transverse seals at the top andbottom of the bag. However, other types of packaging machines may beutilized in accordance with the principles set forth in this applicationand in accordance with the inventive principle of operating and thecheckweighing system in response to the packaging machine or means.

The particular packaging machine 10 illustrated includes a drive motor11 which operates continuously and is or may be regulated by a speedcontrol device (not shown). Output shaft 12 serves to continuously drivecarriage drive 13 which operates the transverse sealing jaws (not shown)to form the discrete packages. A drive shaft 14 serves to drive anoperating shaft 15 for the checkweighing system of the present inventionthrough a one-half speed drive reducer 16. The operating shaft 15 hasmounted thereon for driving in synchronism, a check cam 17 having twolobes 18, 18a spaced 180 degrees apart, a scale selector cam 19 having a180 degree raised portion 20 and a 180 degree detent portion 21, and ascale dump timing switch 22 having a single raised lobe 23 thereon. Asuitable adjustable connection 24 is provided on the shaft 15 to adjustthe phase of the selector cam 19 and the timing cam 22 so that thenumber of packages between the packaging machine 10 and thecheckweighing station may be varied, as will later be described.

As noted above, the preferred embodiment of the checkweighing system ofthe present invention is for controlling a packaging machine 10 havingmultiple filling stations. As is known in the art, these fillingstations may be in the form of time-controlled dispensers, usually usedwith liquid products, or weighing scales, usually used with solidproducts. In the present disclosure for illustrative purposes, abeam-type weighing scale 25 has been illustrated with a hopper 26mounted thereon for holding the charges of material to be packaged. Itwill be understood that another scale 27 identical to the scale 25 ispresent on the other filling side of the packaging machine 10; however,this need be illustrated only in dotted-line outline, it beingunderstood that the operation is the same as that to be described withrespect to the scale 25. The weighing hopper 26 has a pivotal gate 28,which, when operated by solenoid 29 (dotted line position), allows thecharge of material to be dispensed into the package then being formed.

In accordance with the present invention, the packaging machine 10utilizes a number of circuits controlled by the cams 17, 19, 22 in aunique manner to checkweigh the packages being formed without thepossibility of getting out of step with said packaging machine 10regardless of the speed of the machine, the number of dry cycles,packages being inserted or withdrawn from the system or othercontingencies. A pair of input lines 30, 31 is provided to connect thesystem to a suitable potential source (not shown) and a classificationcircuit to perform the reject-accept function is shown at the top of thediagram of the drawing. The reject-accept or classification circuitincludes a relay RY-l in series with an air switch 32 which is normallyopen and operated or closed by an airblast from the air tube 33. Therelay RY-l has contacts RY-la in parallel across the switch 32 to holdthe circuit in once the relay RY-l has been actuated. A check switch 34is also provided in the classification circuit and is raised to completesaid circuit once during each package-making cycle of the packagingmachine 10 by the lobes 18, 18a of cam 17.

Once the switch 34 is brought into contact as shown in the diagram, thecircuit remains closed until the cam 17 releases the same. This meansthat the time during which the relay RY-l is energized is controlled bythe effective length of the lobes 18, 18a. As will be seen later, theselobes also advantageously control the amount of correction fed toweighing scales 25, 27 in the same manner. In order to vary the size ofthe lobes, suitable adjustable extensions 35 may be provided. In thisway, the desired degree of classification or correction action may bemade, such as may be required for any particular ambient condition, typeof material being packaged or other condition.

The relay RY-I has contacts RY-lb that perform the classification ofpackage P situated at checkweighing scale 38. These contacts arenormally in position to complete the circuit through an accept air valvesolenoid 40. Thus, once an airblast has closed the air switch 32 andcheck switch 34 has operated to bring in the circuit, the solenoid 40operates air valve 41 in air supply line 42 which serves to pressurizethe air manifold 43 having openings 44 through which the airblast, timedby the cam 17, is released. This action blows the package P to the rightas viewed in FIG. 1, and into the accept receiving station.

A reject air valve solenoid 45 operates air valve 46 along supply line47 in the situation where the switch 32 has not operated, such as in theinstance where the package P is absent. In this situation, an air blastis provided through the openings 48 from a manifold 49 at a degree angleto the manifold 43 and therefore capable of clearing the area andconveying a lightweight package in a separate reject" depositingposition.

The package P, when positioned for reject or accept" as just described,has come to rest on scale pan 50 of the checkweighing scale 38 eitherdirectly from the packaging machine or froma suitable in-step transferconveyor. The scale 38 is of the high-speed type so as to reach a stablecondition rapidly after the package P has been positioned thereon.Broadly, the scale 38 thus includes beam 51, fulcrum support 52,counterweight 53 and return stop 54. Connected to the beam 51 formovement with the scale pan 50 is an inverted knife edge flag 55 whichforms an integral part of a first air sensor, generally designated bythe reference numeral 56. The sensor 56 includes an air source tube 57having an exit orifice directed across a gap toward and in alignmentwith the mouth of operating tube 33 for the switch 32.

Thus, to review the operation so far, with a package P on the scale pan50, the flag 55 is moved downwardly to open the gap of the sensor 56,allowing pressurized air to enter the tube 33 and move the switch 32 tothe closed position, as shown. The relay RY-l is immediately energizedand held by contacts RY-la and closes the contacts RY-lb, operates theair valve 41 to blow the bag P off the scale pan 50 into the accept"receiving station. lf the flag 55 had not moved out of the gap of thesensor 56 so that the switch 32 had not been closed, then the reject airvalve 46 would have been operated since the contacts RY-lb would havebeen in the other position, and the lightweight bag would have beenremoved to the reject collection station. If the initial blast of theair from the manifolds 43, 49 should rapidly release the scale pan 50 soas to move the flag 55 up into blocking position across the sensor 56,the switch 32 would immediately open; however, because of the holdingcontacts RY-la, the circuit remains in effect for the predeterminedtime; that is, until released by the check switch 34 dropping down fromthe lobe 18a of the cam 17.

The second circuit of major importance in accordance with the presentinvention, is the correction circuit utilized for ad justing the weightsetting of the two scales 25, 27 of the packaging machine 10. Thecorrection circuit includes a relay RY-2 which is energized by a secondair switch 60 and which has holding contacts RY-Za to hold the circuitin once it has been made by movement of the check switch 34 to theclosed position, as shown. The switch 60 is operated by an airblast fromair tube 61; the air being transmitted from a suitable supply tube 62across a gap-forming sensor 63 through which the flag 55 moves. ln theposition shown in the diagram, the package P is considered to be toolight, and accordingly an increase in weight to the appropriate weighinghopper is called for and will be discussed presently. If the flag 55 hadmoved further down as so to clear the gap of the sensor 63 by virtue ofa too heavy package P being present on the checkweigh scale, then it isclear that the switch 60 would have been closed, energizing the relayRY-Z and holding contacts RY-Za. The position of the sensors 56, 63 maybe adjusted relative to the flag 55 by thumbscrews 56a, 63a,respectively. The adjustment moves the respective carriages 56b, 63bwhereby the position for opening the gap to actuate the switches 32, 60may be adjusted. Thus, in effect the differential between the minimumbag weight, as determined by the sensor 56, and the theoretical perfectbag, as delineated between the two positions of the sensor 63, may beadjusted.

To transfer the signal of the condition of the sensor 63, the relay RY-2has contacts RY-2b and RY-2c to operate the selected winding ofservomotors 65, 66 for correcting the scales 25, 27, respectively. Inthe open position of RY-2, winding 67 for rotating the motor 65 (andmotor 66, it is to be understood, includes a corresponding winding, andan opposite winding) is in circuit to cause an increase in the weightsetting (adjust up) in the scale 25. It follows that, in the energizedposition, the contacts RY-Zb close the winding 68 for decreasing theweight or load setting (adjust down) of the scale 25.

The increase and decrease is transferred through suitable drive shaft 69having a pinion 70 and driven gear 71 meshed therewith. The gear 71turns a positioning screw 72 that is operative to move a permanentmagnet 73 in the longitudinal direction along scale beam 74 of the scale25. The scale beam 74 is fabricated of iron or other ferrous metal so asto be attracted by the magnet 73. it will be realized that as the magnet73 is moved along the scale beam 74, the amount of weight necessary todepress scale pan 75 supporting the hopper 26 is appropriately varieddue to change in the effective lever arm. A conventional counterweight76 may be provided to set the original adjustment of the scale beam 74to match the desired predetermined weight of the charge being introducedinto the hopper 26. The adjustment of the magnet 73, and thus the effective weight setting of the scale 25, is accompanied by lighting ofneon indicator lamps 80, 81; the indicator lamp 80 being energizedthrough the winding 68 when the winding 67 is being utilized to cause anincrease correction, and the lamp 81 being energized through the winding67 when the decrease winding 68 has been selected.

The drive circuit for controlling the important concurrent actuation ofthe classification and correction circuits just described includes therelay RY-3. The first set of contacts is RY-Ila in the classificationcircuit, which contacts are normally closed. Therefore, the circuit isoperative as described above as long as the check switch 34 maintainsthe position shown in the drawing. Likewise, contacts RY-3b in thecorrection circuit are normally closed so as to permit operation asdescribed above.

Relay RY-B also controls actuation of an air valve 85 for directing airfrom the supply tube 86 against the bottom of the scale beam 51 toreturn the scale pan 50 to the home position. This is accomplishedthrough normally closed contacts RY-3c that operate the coil 87.

A novel aspect of the drive circuit is the inclusion of delay means tohold the relay RY-3 open until relays RY-l and RY-2 have been actuatedby a switching of the check switch 34 by the cam 17 from the drivecircuit to the companion classification and correction circuits. Ratherthan providing a separate delay device in the circuit, preferably therelay RY-l and relay RY-Z are selected so as to have a shorter pickuptime characteristic than the dropout time characteristic of the relayRY-3. Typically, the relays RY-l, RY-2 may have a pickup time ofapproximately 35 milliseconds whereas the relay RY-3 may have a dropouttime of 85 milliseconds. Thus, it will be seen even with the timerequired for the switch 35 to change contacts between the respectivecircuits working against this time spacing, the contacts RY-3a, RY-3band RY-3c are held open an instant past the time when the relays RY-land RY-Z have been actuated. This means that the companionclassification and correction circuits are set and held by thecorresponding holding contacts RY-la and RY-Za before the package P isblown from the checkweigh scale pan 50, before the correction motors 65,66 are actuated and before the checkweigh scale 38 is returned by theairblast through the valve 85. Thus, no switching of the functionsduring midcycle to cause a faulty classification or faulty correctionsignal is possible.

In accordance with another important feature, the selection of the scale25 or the scale 27 to be controlled by the correction circuit isdetermined in a novel manner by and in response to the packaging machine10. Specifically, the cam 19 mounted on the operating shaft 15 opensselector switch 88 in response to the raised portion 20 and is closed bythe detent portion 21; the latter position serving to actuate relayRY-4. Contacts RY-4a thus serve to select the first motor 65 to receivethe correction during half the time and to select the second motor 66for operation during the remaining half of the time. Thus, it will benoted that the correction signal from the correction circuit is fed toboth the contacts RY-Zb and RY-Zc for the motors 65, 66 during eachcycle, but only one of these contacts is operative, depending on whichlead 89, 89a is selected by the contacts RY-4a to carry the actuatingcurrent from the lead 30. With this arrangement, the scale select signalmay be a low voltage signal rather than sufficient to drive the motors65, 66 which signal is easier to handle and transmit from the packagingmachine 10.

Relay RY-6 is controlled by timing switch 100 operated by cam 22 alsomounted for driving on the shaft 15. Contacts RY-6a are utilized toselect the scale hopper that is, at any particular time, being used tofill a package. in the open position of the relay RY-6 illustrated, thehopper gate 28 associated with the scale 25 is thus being actuated bythe operation of coil 29 and thus the hopper 26 of the first scale 25 isfilling the package being formed. On the opposite side or detent portionof the cam 22, the timing switch 100 energizes the relay RY-6, switchingthe contacts RY-6a to enable the scale 27. It should be noted that withthe arrangement shown in the diagram with the cams 20, 22 in step, anodd number of bags or packages, i.e., one, three, five, etc., isrequired between the packaging machine and the scale pan 50 of thecheckweighing scale 38. This is so, since if a bag is at present beingfilled by the hopper 26 associated with the first scale 25 and thecorrection motor 63 is at the same time being actuated to correct for abag from the same scale, then a bag from the second scale 27 must havepreviously been made and now positioned therebetween.

lf, on the other hand, it is desired to monitor bags directly from thepackaging machine 10 or spaced at any other position along a conveyorwith an even number of bags in between, the operator of the packagingmachine 10 need only shift the phase of cams 2Q, 22 by 180 degrees byoperation of the phase adjustment connection 24. Any suitable detachableconnection that allows the adjustment of the cams 20, 22 with respect toeach other, such as a set screw on either one of the cams 119, 22 issufficient to meet the requirements of this means.

Cycle reset relay RY-7 is operated by a photocell 105 in response tointerruption of the light beam from a lamp 106 by a flag 107 of thescale 25. This means that the hopper gate 28 is thus not opened (dottedline position) even though it has been enabled by shifting of timingswitch MM) until the appropriate weight has been deposited in the scalehopper 26. Thus, it is possible for the cam 22 to switch the timingswitch 100 for filling of a package at the second scale 27 without thegate 28 ever having been opened on that cycle which in turn means that adry cycle and no bag is produced by the first scale 25. Advantageouslythis contingency does not adversely affect the maintenance of thein-step operation since the scale selector switch 88 has now alsoswitched and the weight signal from the checkweighing scale 38 is thusproperly fed to the scale 27 by contacts RY-4a. To prevent the dry cyclefrom causing a false correction reading to be sent to the appropriatescale since no package producing a too light" signal will now appear atthe checkweighing scale 33, a sensing circuit having relay RY-S isprovided to disable the correction circuit through contacts RY-Sa. Therelay RY-S is energized in this circuit and contacts RY-Sa closed by anysuitable energy sensing means looking across the scale pan 50, such asphotocell 110, operated through interruption of a light beam from lamp111 only in the presence of a package P. Furthermore, if during theoperation of the machine, on of the packages P is removed by theoperator for inspection, the absence of said package P from the scalepan 50 does not affeet the correction circuit and no faulty correctionis made.

In view of the foregoing detailed description with reference to thedrawing, it will be realized the checkweighing system of the presentinvention controlled by the operation of the packaging machine 10 offersreal advantages in insuring continuous identification of the packagesand correction of the proper weighing scale 25, 27. A classificationcircuit is actuated concurrently with the correction circuit and delaymeans is provided to insure energizing and setting of the circuits priorto energizing the drive circuit to perform the intended operations toprevent midcycle changes. The sensing circuit at the checkweighing scaleinsures that faulty corrections are not made as a result of dry cyclesor a bag having been removed from the stream.

In this disclosure, there is shown and described only the preferredembodiment of the invention, but, as aforementioned, it is to beunderstood that the invention is capable of various changes ormodifications within the scope of the inventive concept as expressed bythe accompanying claims.

We claim:

11. A high-speed checkweighing system for monitoring packages from anindependently operating packaging means and maintaining constant weightthereof comprising at least first and second filling means fordispensing predetermined charges of material to be packaged, means foradjusting the setting of each of said filling means to change the weightof said charge; means responsive to said packaging means operativeduring each packaging cycle to identify said first and second fillingmeans used for filling each package being checkweighed, checkweighingmeans for weighing said packages and feedback correction meansresponsive to said checkweighing means and the identification means,whereby correction of the proper filling means by operating thecorresponding adjusting means and synchronism with said packaging meansis assured.

2. The system of claim 1 wherein each of said filling means comprises ascale and a hopper on said scale for weighing the charges of material.

3. The system of claim ll wherein said identification means includes aselector switch responsive to said packaging means and means foroperating said selector switch in response to each packaging cycle toconnect said correction means to the adjusting means of said first andsecond filling means on successive packaging cycles.

4. The system of claim 3 wherein said selector switch is operated by acam, substantially degrees of said cam being a raised portioncorresponding to said first filling means and 180 degrees being a detentportion corresponding to said second filling means, whereby two scalesare controlled.

5. The system of claim 3 wherein said identification means furtherincludes a timing switch responsive to said packaging means for fillingsaid packages from said first and second filling means on successivepackaging cycles, said operating means serving to operate said timingswitch in synchronism with said selector switch.

6. The system of claim 5 wherein is provided a cycle reset relayresponsive to said packaging means for each of said filling meansresponsive to the weight therein to disable the same for a dry cyclewhen the required weight is not made to minimize formation ofunderweight packages.

7. The system of claim 5 wherein is provided phase adjustment means insaid operating means between said selector switch and said timingswitch, whereby the number of packages between said packaging means andsaid checkweighing means may be varied.

8. The system of claim 5 wherein the number of filling means is limitedto two and the number of packages between said packaging means and saidcheckweighing means is even whereby filling of a package by said firstfilling means is accompanied in point of time by checkweighing of apackage filled by said second filling means and correcting of saidsecond filling means.

9. The system of claim 5 wherein the number of filling means is limitedto two and the number of packages between said packaging means and saidcheckweighing means is odd whereby filling of a package by said firstfilling means is accompanied in point of time by checkweighing of apackage filled by said first filling means and correcting the same.

10. A high-speed checkweighing system for monitoring packages frompackaging means and maintaining constant weight thereof comprising afilling means for dispensing predetermined charges of material to bepackaged, means for adjusting the setting of said filling means tochange the weight of said charge, checkweighing means including a scalepan for weighing at least some of said packages, a classificationcircuit having a first sensor on said checkweighing means, means toclassify said packages in response to said classification circuit, saidpackages being rejected when below a predetermined minimum weight issensed and accepted when above, a correction circuit including a secondsensor on said checkweighing means for determining the weight variationof said packages, feedback correction means responsive to saidcorrection circuit to operate said adjusting means to increase thesetting of said filling means if a lightweight package is produced andto decrease the setting if a heavyweight package is produced and a checkswitch means responsive to said packaging means for energizing of saidclassification circuit and said correction circuit, wherebyclassification and checkweighing is concurrently performed for each ofsaid packages.

11. The system of claim 10 wherein each of said filling means comprisesa scale and a hopper on said scale for weighing the charges of material.

12. The combination of claim 10 wherein said sensors comprise pneumaticswitches, means for projecting an airstream across a gap and fiag meansmounted on said scale to energize the respective circuit.

13. The combination of claim 10 wherein is further provided a holdingrelay in each of said circuits whereby once energized the circuitsremain in the same state until released by said check switch means.

14. The combination of claim 10 wherein is provided delay means in saidclassification and correction circuits whereby switching of theclassification and checkweighing actions during a single cycle isavoided.

15. The combination of claim 10 wherein said classification meansincludes first and second air manifolds positioned at 90 degrees withrespect to each other adjacent said scale pan, discharge openings insaid manifolds looking across said scale pan, and an air source forgenerating a blast of air from said openings to sweep said packages fromsaid scale pan.

16. The combination of claim 10 wherein is further provided a sensingcircuit including an energy-sensing means looking across the scale panof said checkweighing means to detect the presence of a package,enabling switch means only in said correction circuit responsive to saidenergy-sensing means to enable operation of said correction circuit inthe presence of a package but without effect on said reject-acceptcircuit so as to allow clearance of said scale pan during each cycle.

17. The combination of claim 10 wherein is further provided a secondfilling means for dispensing predetermined charges of material to bepackaged, means for adjusting the setting of said second filling meansto change the weight of said charge, means responsive to said packagingmeans to identify the filling means used for filling each package beingcheckweighed, said correction means being responsive to saidcheckweighing means and said identification means, whereby correction ofthe proper filling means by operating the cor responding adjusting meansand synchronism with said packaging means is assured.

18. The combination of claim 10 wherein is further provided cam meansresponsive to said packaging means for controlling said check switchmeans for energizing said circuits, whereby the energizing of saidcorrection and classification circuit is at a fixed time during eachpackaging cycle and for a fixed time period.

19. The combination of claim 18 wherein said cam means is adjustable topermit varying of the amount of correction and classification actionduring each packaging cycle.

20. The combination of claim 10 wherein is provided scale return meansoperative to return the scale pan to home position in response to theswitching of said check switch means for energizing said classificationand correction circuits.

21. The combination of claim 20 wherein said scale includes a pivotalbeam, and said return means includes means for projecting a fluid streamagainst said beam.

1. A high-speed checkweighing system for monitoring packages from anindependently operating packaging means and maintaining constant weightthereof comprising at least first and second filling means fordispensing predetermined charges of material to be packaged, means foradjusting the setting of each of said filling means to change the weightof said charge; means responsive to said packaging means operativeduring each packaging cycle to identify said first and second fillingmeans used for filling each package being checkweighed, checkweighingmeans for weighing said packages and feedback correction meansresponsive to said checkweighing means and the identification means,whereby correction of the proper filling means by operating thecorresponding adjusting means and synchronism with said packaging meansis assured.
 2. The system of claim 1 wherein each of said filling meanscomprises a scale and a hopper on said scale for weighing the charges ofmaterial.
 3. The system of claim 1 wherein said identification meansincludes a selector switch responsive to said packaging means and meansfor operating said selector switch in response to each packaging cycleto connect said correction means to the adjusting means of said firstand second filling means on successive packaging cycles.
 4. The systemof claim 3 wherein said selector switch is operated by a cam,substantially 180 degrees of said cam being a raised portioncorresponding to said first filling means and 180 degrees being a detentportion corresponding to said second filling means, whereby two scalesare controlled.
 5. The system of claim 3 wherein said identificationmeans further includes a timing switch responsive to said packagingmeans for filling said packages from said first and second filling meanson successive packaging cycles, said operating means serving to operatesaid timing switch in synchronism with said selector switch.
 6. Thesystem of claim 5 wherein is provided a cycle reset relay responsive tosaid packaging means for each of said filling means responsive to theweight therein to disable the same for a dry cycle when the requiredweight is not made to minimize formation of underweight packages.
 7. Thesystem of claim 5 wherein is provided phase adjustment means in saidoperating means between said selector switch and said timing switch,whereby the number of packages between said packaging means and saidcheckweighing means may be varied.
 8. The system of claim 5 wherein thenumber of filling means is limited to two and the number of packagesbetween said packaging means and said checkweighing means is evenwhereby filling of a package by said first filling means is accompaniedin point of time by checkweighing of a package filled by said secondfilling means and correcting of said second filling means.
 9. The systemof claim 5 wherein the number of filling means is limited to two and thenumber of packages between said packaging means and said checkweighingmeans is odd whereby filling of a package by said first filling means isaccompanied in point of time by checkweighing of a package filled bysaid first filling means and correcting the same.
 10. A high-speedcheckweighing system for monitoring packages from packaging means andmaintaining constant weight thereof comprising a filling means fordispensing predetermined charges of material to be packaged, means foradjusting the setting of said filling means to change the weight of saidcharge, checkweighing means including a scale pan for weighing at leastsome of said packages, a classification circuit having a first sensor onsaid checkweighing means, means to classify said packages in response tosaid classification circuit, said packages being rejected when below apredetermined minimum weight is sensed and accepted when above, acorrection circuit including a second sensor on said checkweighing meansfor determining the weight variation of said packages, feedbackcorrection means responsive to said correction circuit to operate saidadjusting means to increase the setting of said filling means if alightweight package is produced and to decrease the setting if aheavyweight package is produced and a check switch means responsive tosaid packaging means for energizing of said classification circuit andsaid correction circuit, whereby classification and checkweIghing isconcurrently performed for each of said packages.
 11. The system ofclaim 10 wherein each of said filling means comprises a scale and ahopper on said scale for weighing the charges of material.
 12. Thecombination of claim 10 wherein said sensors comprise pneumaticswitches, means for projecting an airstream across a gap and flag meansmounted on said scale to energize the respective circuit.
 13. Thecombination of claim 10 wherein is further provided a holding relay ineach of said circuits whereby once energized the circuits remain in thesame state until released by said check switch means.
 14. Thecombination of claim 10 wherein is provided delay means in saidclassification and correction circuits whereby switching of theclassification and checkweighing actions during a single cycle isavoided.
 15. The combination of claim 10 wherein said classificationmeans includes first and second air manifolds positioned at 90 degreeswith respect to each other adjacent said scale pan, discharge openingsin said manifolds looking across said scale pan, and an air source forgenerating a blast of air from said openings to sweep said packages fromsaid scale pan.
 16. The combination of claim 10 wherein is furtherprovided a sensing circuit including an energy-sensing means lookingacross the scale pan of said checkweighing means to detect the presenceof a package, enabling switch means only in said correction circuitresponsive to said energy-sensing means to enable operation of saidcorrection circuit in the presence of a package but without effect onsaid reject-accept circuit so as to allow clearance of said scale panduring each cycle.
 17. The combination of claim 10 wherein is furtherprovided a second filling means for dispensing predetermined charges ofmaterial to be packaged, means for adjusting the setting of said secondfilling means to change the weight of said charge, means responsive tosaid packaging means to identify the filling means used for filling eachpackage being checkweighed, said correction means being responsive tosaid checkweighing means and said identification means, wherebycorrection of the proper filling means by operating the correspondingadjusting means and synchronism with said packaging means is assured.18. The combination of claim 10 wherein is further provided cam meansresponsive to said packaging means for controlling said check switchmeans for energizing said circuits, whereby the energizing of saidcorrection and classification circuit is at a fixed time during eachpackaging cycle and for a fixed time period.
 19. The combination ofclaim 18 wherein said cam means is adjustable to permit varying of theamount of correction and classification action during each packagingcycle.
 20. The combination of claim 10 wherein is provided scale returnmeans operative to return the scale pan to home position in response tothe switching of said check switch means for energizing saidclassification and correction circuits.
 21. The combination of claim 20wherein said scale includes a pivotal beam, and said return meansincludes means for projecting a fluid stream against said beam.